[@Windicator]I admit I may need to adjust the energy costs, but I still can't seem to justify not having an Energy stat.

But you get my point, yes? It's as much about the DM as it is the players and the items and enemies included in the game. Don't give heaps of experience, that way the upgrade-a-stat or be able to level up dichotomy remains a balance on the players, because investing more in stats means taking more BattleExp to Digivolve (when the DM lets them.)